/**
 * Created with IntelliJ IDEA.
 * Description:
 * User:${USER}
 * Date:${YEAR}-${MONTH}-${DAY}
 * ${TIME}
 */
public class Main {
    public static void main(String[] args) {
        System.out.println("Hello world!");
    }

    public String addBinary(String a, String b) {
        StringBuffer s=new StringBuffer();
        int aa=a.length()-1;
        int bb=b.length()-1;int t=0;
        while(aa>=0||bb>=0||t!=0){
            if(aa>=0)t+=a.charAt(aa--)-'0';
            if(bb>=0)t+=b.charAt(bb--)-'0';
            s.append((char)((char)t%2+'0'));
            t=t/2;
        }
        return s.reverse().toString();
    }
}